Manganese hyperaccumulation from non-contaminated soil in Chengiopanax sciadophylloides Franch. et Sav. and its correlation with calcium accumulation

Abstract

The objective of this study was to explore the ability of Chengiopanax sciadophylloides Franch. et Sav. to hyperaccumulate manganese (Mn). We were particularly interested in (1) Mn uptake ability relative to soil-Mn availability, (2) the potential use of this species in phytomining, and (3) potential key physiological factors associated with Mn hyperaccumulation ability. Among plants sampled from 17 locations in their native Japan provenance, the maximum foliar Mn concentration was 23,000 mg kg−1 dry weight (dw; mean: 11,000 mg kg−1). Soils from all sites examined contained low to normal Mn concentrations. There were no significant relationships detected between several soil factors and foliar Mn concentrations, although we found a strong positive correlation between foliar Mn and calcium (Ca) concentrations. Half of the foliar Mn was readily extractable with water, and almost all Mn was extractable with hydrochloric acid (HCl). Furthermore, a highly purified Mn compound was precipitated from leaf ash solutions when pH was adjusted to 8–10. We demonstrated that C. sciadophylloides has an extraordinary Mn-accumulating ability in non-contaminated soil and that Ca accumulation is correlated with Mn hyperaccumulation. We also showed that collecting Mn from C. sciadophylloides is easy and straightforward. We discuss the potential for using the plant in Mn phytomining.